Air and water purification using continuous breakpoint halogenation and peroxygenation

ABSTRACT

A process for optimizing the rate of oxidation using a combination of halogen, e.g. chlorine donors and peroxygen, e.g. potassium monopersulfate. The peroxygen compound elevates the oxidation-reduction potential of the body of water being treated. Simultaneously, a halogen donor is added to the body of water to maintain a PPM level of free halogen sufficient to insure sanitization. The feed rates and concentrations of both oxidizers are optimized so as to achieve and maintain the targeted parameters. A high level of oxidation is maintained which removes by-products from the water and surrounding air.

This invention is related to co-pending application Ser. No. 09/206,809,entitled "Air and Water Purification Using Continuous BreakpointHalogenation" the contents of which are herein incorporated byreference.

FIELD OF THE INVENTION

This invention relates to the maintenance of aquatic facilities, and inparticular, to the optimization of the feed rates of asanitizer/oxidizer and peroxygen compound to eliminate the accumulationof undesirable halogenated compounds, thereby increasing water and airquality within such facilities.

BACKGROUND OF THE INVENTION

The use of closed recirculating water reservoirs for use by the generalpublic, for example, swimming pools, spas, hot tubs, decorativefountains, cooling towers and the like, has led to a variety of waterquality problems. For instance, improper chemical balances in the watercan lead to various types of contamination including bacterial and viralcontamination.

The use of chemical sanitizers is a fairly standard water sanitationmethod. Addition of so-called halogen donor compounds, such as chlorineor bromine are effective sanitizers so long as they are maintained atwell defined and constantly controlled concentration levels in thewater. It is important that the concentration of these chemicalsanitizers is not allowed to become too high which may cause irritationto the users and damage to the water system. Insufficient sanitizersresult in a contaminated condition.

The difficulties in maintaining a proper balance of sanitizers may arisefrom numerous load factors that are difficult, if not impossible, topredict. For instance, in a pool the load factor is typically caused byvarying numbers of users. In hot tubs the use of air jets and high watertemperatures tend to destroy or remove the sanitizer from the water.Cooling towers are subject to environmental conditions, such asfluctuations in temperature. Indoor decorative fountains may be affectedby the air quality in the building, while the fountain water can alsoaffect the air in the building.

Various testing devices exist for determining the chemical balance ofthe water of pools, spas and the like, for example, colormetric chemicaltest kits are available that utilize liquid droplets, test strips ortablets which dissolve in the water to indicate a particular level orconcentration of sanitizing agents. By removing a test sample of water,for example via a scoop or cup, a seemingly representative sample isdeemed to have been taken. A staining agent is then added by means suchas an eye dropper or the like. The degree of staining relates to theamount of sanitizer in the water. The amount of sanitizer present isdetermined by visually comparing the degree of coloring of the testsample against a test scale previously formulated. Further complicatingthe task of maintaining sanitary conditions in such bodies of water isthe fact that studies now indicate there is little correlation betweenthe free halogen, e.g. chlorine, residual readings which are normallyused to monitor such bodies of water and the actual bacteriologicalquality of the reservoirs themselves. Pool and spa maintenance officialshave long gone under the assumption that maintaining a free chlorineresidual of two milligrams per liter or two parts per million willinsure a safe water condition. Thus, the parts per million reading whichis determined via the stain comparison, is actually a reflection of thesum of the free chlorine and combined chlorine compounds such aschloramine which are present in the water. These combined chlorinederivatives do not protect from bacteria and/or viral contamination.Additionally, since organic and chemical loading drastically reduce theability of free chlorine to overcome bacteria, the available freechlorine test kits are of questionable value unless the exact levels oforganic contaminants and the particular pH of the water being tested isknown.

U.S. Pat. No. 4,752,740 suggests the use of monitoring theoxidation-reduction potential (ORP) as a method of measuring thesanitization levels of water. ORP defines the potential of a sanitizersuch as chlorine, bromine or ozone to react with various contaminants.These compounds are known as oxidizers and have the property of "burningoff" impurities in the water, for example, body wastes, algae andbacteria. The use of an ORP sensor allows the pool maintenance engineerto measure the potential generated by the active form of the sanitizerand not the inactive forms such as the combined chlorine derivatives.Additionally, ORP monitoring has an advantage in that it is an ongoingelectronic process requiring no test chemicals or agents and monitoringof sanitation levels is constantly performed as opposed to beingperformed on some predetermined schedule basis. Since the potential fordisease transmission due to organic loading is far more significant inpublic spas and pools, use of ORP measurement could be of great benefitin reducing the risk of contamination and disease transmission.

In accordance with standards set forth by the World Health Organizationin 1972, maintenance of an ORP level of 650 millivolts is deemed toresult in a water supply that is disinfected and in which viralinactivation is virtually instantaneous.

Chlorine is the most widely used oxidizer in the aquatic industry, theprimary use being for sanitation of the water in pools and spas.Chlorine, being an oxidizer, is also involved in oxidation reactionswith various organics, as well as inorganic and organic nitrogen basedsubstances such as urea, uric acid, amino acids, etc. One of thedrawbacks of chlorine is the production of chlorinated byproductsresulting from incomplete oxidation. These byproducts are often volatileand produce undesirable side effects such as irritation of the eyes,sinuses, skin, foul smelling air, and corrosion of air handlingequipment.

The health department generally regulate the concentration of Free (HOCL& OCL) chlorine in the water. In some locations, sufficient HOCL is notavailable to maintain a sufficient rate of oxidation of the demand beingcontributed to the water. This allows for the accumulation of theseundesirable substances. Substances which oxidize followingsubstoichiometric oxidation react with the chlorine producingsubstoichiometric and/or stoichiometric compounds. Further oxidationwith HOCL eventually leads to increased concentration of substances thatfollow stoichiometric oxidation, such as monochloramines. If enough HOCLis not maintained to meet the stoichiometric ratios needed to driveoxidation of the chloramines, no demand on the HOCL is experienced.However, when the chlorine donor(s) are controlled using ORP controlwith an optimized ORP setting of between 780-800 mV, the bufferingeffect chloramines place on the ORP becomes a significant factor. Thebuffering effect provided by the chloramines reduces the impact on ORPprovided by the addition of more chlorine donor(s). The controller feedsmore chlorine donor(s) to achieve the optimized ORP. This often leads tolevels of Free Chlorine which exceed local maximum limits. In order tomeet the maximum limits of free chlorine, the ORP is reduced so as tonot exceed the established limit. This allows for the volatilechlorinated compounds to accumulate, thereby increasing the partialpressure which promotes fouling of the air.

Numerous attempts have been made at addressing this problem. "Shocking"of the pool water requires dosing the water with stoichiometricconcentrations of chlorine to oxidize the substances. One problem withthis method is that there cannot be any bathers present due to theexcessive concentrations of chlorine required to meet the stoichiometriclevels needed when said undesirable substances have been allowed toaccumulate. Another issue is this method is generally applied after thesymptoms have appeared, i.e. high combined chlorine, foul odors, etc. Inmany cases this method fails to rid the water and air of thesesubstances since the concentration of chlorine required is at best arough estimate (incorporates measuring the combine chlorine in thewater). Measuring the concentration of combined chlorine in the waterdoes not take into consideration the accumulated demand that isnon-aqueous, e.g. that accumulated on the filter media, walls of thepools, etc. As the chlorine levels rise, some of the accumulated demandis liberated. This gives the appearance that the system had not beendriving breakpoint when indeed it probably did for awhile. The fact thatthe free chlorine levels drop considerably, and the combined chlorinelevel still appears, is an indication the HOCL must have oxidized thecombined chlorine and/or accumulated demand, thereby providing a sourceof readily available oxidizable substances not originally detected inthe water. When the free chlorine levels rise, they oxidize substancesin the filters and the remaining system. This releases more substancesinto the water which were not accounted for, the stoichiometric ratio ofHOCL is overtaken, and breakpoint is not achieved.

Ozone has been used as a side stream treatment to destroy theseundesirable substances. While effective, ozone cannot be applied to thebulk water of the pool where the contaminants are being added. Also,since ozone cannot be used as a stand-alone treatment since it cannotmaintain a residual in the water, chlorine or bromine is used as theprimary sanitizer. Besides being expensive and often requiring extensivedeozonation equipment, e.g. such as activated carbon, ozone destroyschlorine by attacking the hypochlorite ions, thereby further increasingoperational and maintenance cost.

Bromine is sometimes used in place of chlorine because of the belief itdoes not produce the air fouling byproducts produced by chlorine.However, while bromamines are not as volatile as chloramines, they dopossess an odor and irritate the eyes. Bromine also requires an oxidizersuch as chlorine or ozone to activate the bromide ion. Operating coststend to be high and it is often difficult to maintain water qualitysince no easy methods are available for differentiating between free orcombined bromine. Also, hydantoin, an additive commonly used topelletize the bromine chlorine combination, reduces the oxidizing powerof the bromine as the hydantoin accumulates in the water. This makes itmore difficult to reduce the accumulation of undesirable brominatedcompounds.

Non-chlorine shock treatments incorporating peroxygen compounds, e.g.potassium monopersulfate (MPS) have been sold under the brand nameOXY-BRITE for addressing the chloramine issue. Despite the applicationof this product following manufacturer's guidelines, many pools continueto experience chronic air and water quality problems. The method ofshock feeding is a means of addressing the symptoms resulting after theproblem makes them apparent, e.g. high chlorine concentration and foulodors. MPS is approved for use as a shock treatment while bathers arepresent. However, when applied to systems using chlorine donor(s) whichare fed using ORP control, the system experiences undesirable sideeffects from shock feeding MPS. The addition of MPS increases the ORP ofthe chlorine donor(s) system. When MPS is added, the ORP of the systemrises above that provided by the chlorine donor(s) As long as the ORPvalue remains above the set point established for the chlorine donor(s)system, no chlorine donor is fed. Since many of the contaminantsentering the water do not react directly with MPS without first beingoxidized by the chlorine donor(s), these substances further accumulate,thereby compounding the problem.

SUMMARY OF THE INVENTION

This invention incorporates an innovative process that allows theaquatic facility to maintain the desired ORP and oxidize the chlorinatedvolatile substances in the bulk water, while not exceeding the freechlorine limits established by local health departments.

This process incorporates optimization of the rate of oxidation bycontrolling the feedrate and ratio of two oxidizers, the primaryoxidizer being a halogen donor, e.g. trichloroisocyanuric acid,dichloroisocyanuric acid, sodium bromide, hydantoin based bromines,gaseous chlorine, calcium hypochlorite, sodium hypochlorite, lithiumhypochlorite and mixtures thereof; the other being a peroxygen compoundselected from hydrogen peroxide, sodium peroxide, sodium perborate,potassium monopersulfate, sodium peroxydisulfate, potassium peroxide,potassium perborate, sodium monopersulfate, potassium peroxydisulfate,ammonium peroxydisulfate, ammonium monopersulfate and mixtures thereof.In a preferred embodiment the peroxygen compound is potassiummonopersulfate (MPS). The ratio of MPS to halogen donor, e.g. chlorinedonor(s) is optimized to sustain the desired PPM range of chlorine,while achieving an ORP of 780-820 mV. By optimizing and controlling thefeedrate and ratios of a halogen donor to maintain the desired ORP, therate of oxidation is maintained at a level sufficient to prevent theaccumulation of undesirable halogenated byproducts. When applied to anaquatic facility, the effects of poor air and water quality can bereduced and even eliminated.

The process optimizes the ORP by incorporating the necessary processcontrol and feed equipment to sustain a set-point thereby controllingthe concentration of undesirable by-products in the water.

An objective of the invention is to eliminate volatile halogenatedcompounds from water and air by maintaining a level of oxidationpotential. The feedrate and ratio of halogen donor and peroxygencompound are optimized to sustain the desired PPM range of halogen andsustain an ORP of 780-820 mv. Sustaining these parameters will preventor even reverse the accumulation of combined halogen and otherhalogenated volatile compounds which contaminate the air and water ofaquatic facilities, in particular indoor aquatic facilities.

Another objective of the invention is to teach a process of operating anaquatic facility under conditions of "Continuous Breakpoint Halogenationand Peroxygenation".

Yet another objective of the invention is to improve the air qualityaround closed water systems by removal of halogenated compounds throughre-absorption followed by oxidation thereof with, e.g. HOCL.

Other objectives and advantages of this invention will become apparentfrom the following description taken in conjunction with theaccompanying drawings wherein are set forth, by way of illustration andexample, certain embodiments of this invention. The drawings constitutea part of this specification and include exemplary embodiments of thepresent invention and illustrate various objects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic representation of the process of the instantinvention.

FIG. 2 is a Circuit Diagram of the Air and Water Flow in the test deviceaccording to Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is to be understood that while a certain form of the invention isillustrated, it is not to be limited to the specific form or arrangementof parts herein described and shown. It will be apparent to thoseskilled in the art that various changes may be made without departingfrom the scope of the invention and the invention is not to beconsidered limited to what is shown in the drawings and described in thespecification.

Referring to FIG. 1, a typical indoor aquatic facility is characterized.Water from the pool or spa flows past an ORP sensor. Optionally, thewater may further flow past a sensor which measures total dissolvedsolids (TDS), temperature and pH. Output from the ORP sensor istransmitted to a controller which calls for the addition of both ahalogen donor source and a peroxygen source to the pool water inaccordance with selected process parameters.

An innovative process has been developed that allows the aquaticfacility to maintain the desired ORP, oxidize the halogenated volatilesubstances in the bulk water, while not exceeding the free halogenlimits established by local health departments.

Oxidation Reduction Potential is a qualitative measurement of theoxidation or reduction power of a solution. ORP controllers have beenused in aquatics since 1972 when the Stranco Company developed andintroduced these systems to the industry. Despite the use of ORPcontrollers in tens of thousands of aquatic facilities, the issue ofpoor air and water quality continues to be the universal and primaryproblem with indoor aquatic facilities.

While ORP has been established as the primary indicator of determiningthe inactivation rates of various bacteria and viruses, dosing aquaticwater with part per million (PPM) measurement of halogen has been themethod used for meeting the oxidation needs of the aquatic facility. Forexample, while 650 mV is commonly used as the minimum required oxidationpotential to ensure sanitized conditions in a pool or spa, the healthdepartments still require PPM levels of halogen, e.g. chlorine.

Despite maintaining health departments levels of halogen and/oroperating with ORP levels in excess of 650 mV, following prescribedmethods of superchlorination (breakpoint chlorination) as described onthe product literature and in the "Certified Pool Operators" (CPO)training course, the problems resulting from incomplete oxidation arewidespread.

This process incorporates optimizing the rate of oxidation bycontrolling the feedrate and ratio of two oxidizers, the primaryoxidizer being a halogen donor(s), the other being a peroxygen compound,e.g. Potassium monopersulfate (MPS). The ratio of MPS to halogendonor(s) is optimized to sustain the desired PPM range of halogen, whileachieving an ORP of 780-820 mV. By optimizing and controlling thefeedrate and ratios of a halogen donor to maintain the desired ORP, therate of oxidation is sufficient to prevent the accumulation ofundesirable chlorinated byproducts. When applied to an aquatic facility,the effects of poor air and water quality can be reduced and eveneliminated.

It has been demonstrated that optimizing the ratio of halogen donor(s)to peroxygen compound, while controlling their combined feedrate usingORP, effectively reduces or eliminates the problems resulting from theaccumulation of volatile halogenated substances. This is achieved whilemaintaining lower PPM levels of free halogen than is otherwise requiredin a strictly halogen donor(s) system.

This process involves: achieving and sustaining an optimum concentrationof free halogen, e.g. free chlorine, of between 0.2-10 ppm, addition ofperoxygen, e.g. MPS to raise the solution's ORP to 750-850 mV(preferably 760-800 mV), controlling the feed of both oxidizers using anORP controller, optimizing the ratio of halogen donor(s) to peroxygencompound to sustain the optimized halogen donor(s) while achieving thedesired ORP. By sustaining these conditions, the problems created bypoor air and/or water quality resulting from the presence of theseundesirable byproducts can be reversed.

This invention ensures a sustained high rate of oxidation in the bulkwater of the pool, spas, and other aquatic water systems despite thepresence of accumulated demand. It has been found that the undesirablebyproducts cannot be sustained in an environment possessing this levelof oxidation potential. Therefore, by implementing this invention, theaquatic facility will be operating under the conditions of "ContinuousBreakpoint Chlorination".

By operating in the conditions described, the byproducts produced duringthe initial step of oxidation are not allowed to accumulate. Thebyproducts are an intermediate step in the continuing process ofoxidation. While these byproducts are initially produced, they are notallowed to accumulate, and shortly thereafter, are destroyed by thecontinued oxidation. By preventing the accumulation of these volatilebyproducts, their respective partial pressures are minimized, and theproblems of poor air quality are minimized or prevented. Also, inaquatic facilities that currently experience these problems, byimplementing this application, the problems of poor air qualityresulting from these chlorinated compounds can be reversed throughre-absorption of the volatile chlorinated compounds, followed byoxidation, even while maintaining substoichiometric levels of freehalogen. The re-absorption process follows Henry's Law of Diffusion.

This development is important to the aquatics industry since itsimplementation means halogen feedrates can be controlled below maximumregulated levels while preventing or even reversing the accumulation ofcombined halogen and other chlorinated volatile compounds whichcontaminate the air and water of aquatic facilities, in particular,indoor aquatic facilities.

EXAMPLE 1

A testing device as shown in FIG. 2 was designed and built to simulatethe water and air environment of an indoor aquatic facility. The systemwas designed to control the following:

H₂ O temperature;

Air circulation rates;

Air exchange rates;

Water turnover rates (filtered water);

Water exchange rates.

Instrumentation for automatic monitoring and recording of ORP and pHwere incorporated.

A condenser was installed in the air circulation system. The condenserallowed for scheduled sampling of the condensate.

A micro-titration system was incorporated for precise feed of variousreagents for adjusting ORP, pH, etc.

The test device was initially prepared for use by the addition of waterto 50% of the skimmer line. The tank representing the surge pit wasfilled to 50%. The tank lid was sealed.

Condensate samples were collected by chilling the air prior to the aircirculation pump. Condensate was collected for 20 minutes, the measuredsample was tested using standard DPD methods for chlorine thatincorporated a HACH DR2000 spectrophotometer.

Laboratory grade ammonium chloride was used as the nitrogen source forthe generation of chloramines. A measured amount was added to the waterof the test device. The water and air circulation pumps were activatedand adjusted to achieve desired circulation and exchange rates.

A measured dosage of chlorine in the form of 5.25% liquid bleach wasadded to the water to induce the formation of combined chlorine. Afterproviding sufficient contact time, incremental dosages of bleach wereadded to achieve and sustain the desired ORP of 800 mV. Condensate andwater samples were periodically tested for free and total chlorine usingstandard methods. ORP and pH readings were also recorded.

                  TABLE 1                                                         ______________________________________                                        Lapsed Time                                                                             ppm free   ppm combined                                                                             ppm combined                                  (minutes) (water)    (water)    (condensate)                                  ______________________________________                                         0        0.24       1.50       0.00                                           45       4.50                  4.35                                           90       4.46                  2.18                                          135       4.40                  1.75                                          180       4.32                  1.45                                          225       4.26                  1.40                                          ______________________________________                                    

Results demonstrate that a comparable rate of chloramine destruction canbe achieved while sustaining lower concentrations of free availablechlorine, at an oxidation potential of approximately 780 mV.

EXAMPLE 2--FIELD TRIAL

An indoor aquatic facility with a 166,500 gallon lap-pool, and a 14,400gallon splash pool incorporating a water slide had experienced chronicair and water quality problems. Combined chlorine in the water of bothpools (water is mixed in the surge tank), was consistently above 1.00ppm. Odors in the air were strong from chloramines.

The facility had utilized an ORP control system with calciumhypochlorite as the primary sanitizer/oxidizer. Potassium monopersulfatehad been fed at 4 times the suggested concentrations as described on themanufacturer's directions. Superchlorination had been incorporated every3 weeks at a concentration three times that taught by the CertifiedOperators Training (CPO), and the Aquatic Facilities Operator (AFO)course.

Initially, condensate from the air handling systems dehumidifier wascollected and tested using standard methods FAS-DPD test for chlorine.

Day One--3:00 pm . . . 0.6 ppm total chlorine

Day One--7:00 pm . . . 0.8 ppm total chlorine

Day Two--9:00 am . . . 0.8 ppm total chlorine

Initially, the system was started using calcium hypochlorite to achievethe targeted ORP of 780 mV. The Free Chlorine levels needed to sustainthe ORP at 780 mV generally ranged from 4 to 6 ppm, with one dayrequiring 18 ppm during a high chlorine demand period.

The two oxidizer approach in accordance with the teachings of theinstant invention was then instituted using calcium hypochlorite andpotassium monopersulfate. The oxidizers' feed rate was optimized toachieve the desired free chlorine concentration in the water (1.5-2.0ppm), while sustaining the targeted ORP of 780 mV using monopersulfate.

Within 3 days of implementing the new program, the combined chlorine inthe water dropped to undetectable levels using FAS-DPD test for chlorine& Total Oxidant. Free chlorine was consistently between the 1.0-2.0 ppm,and ORP was held at 780 mV±1.0%. The odors and skin and eye irritationproblems were eliminated.

To help quantify the reduction in chloramines from the air, condensatesamples were later tested following standard DPD methods.

Day One--6:30 am . . . 0.0 ppm (no color change after 2 minutes)

Day One--7:30 pm . . . 0.0 ppm (no color change after 2 minutes)

Day Two--9:00 am . . . 0.0 ppm (no color change after 2 minutes)

Along with the dramatic improvements in air and water quality, chemicaluse dropped:

    ______________________________________                                        Chemical used  Before (lbs/week)                                                                         After (lbs/week)                                   ______________________________________                                        Monopersulfate 74          55                                                 Calcium hypochlorite                                                                         80          25                                                 Chlorine shock 69           0                                                 ______________________________________                                    

Although the invention is described in terms of a specific embodiment,it will be readily apparent to those skilled in this art that variousmodifications, rearrangements and substitutions can be made withoutdeparting from the spirit of the invention. The scope of the inventionis defined by the claims appended hereto.

What is claimed is:
 1. A process for removing volatile halogenatedcompounds including chloramines and/or bromamines from the air andtreating a body of water in an indoor aquatic facilitycomprising:disposing an oxidation-reduction potential (ORP) sensor influid communication with a body of water within said facility;continuously monitoring the ORP of said body of water; comparing themonitored ORP to a set-point value calculated to be within a rangeeffective to permit oxidation of said volatile halogenated compounds,wherein the effective range of ORP is from 750 mv-850 mv; adding ahalogen donor source in an amount and at a rate sufficient to realize anoptimum free halogen level sufficient to sanitize said body of water;adding a peroxygen compound at a rate and in an amount sufficient tomaintain the ORP within said effective range; optimizing the ratio ofhalogen donor source to peroxygen compound to sustain the optimum freehalogen level while maintaining the effective ORP value; maintaining asustained high rate of oxidation in said body of water sufficient tocause the volatile halogenated compounds in the air to be reabsorbedtherein; and oxidizing the reabsorbed compounds.
 2. The processaccording to claim 1 wherein said halogen donor source is selected fromthe group consisting of trichloroisocyanuric acid, dichloroisocyanuricacid, sodium bromide, hydantoin based bromines, gaseous chlorine,calcium hypochlorite, sodium hypochlorite, lithium hypochlorite andmixtures thereof.
 3. The process according to claim 1 wherein theeffective range of ORP is from 760 mv-800 mv.
 4. The process accordingto claim 1 wherein the optimum free halogen level is within a range of0.2 to 10.0 ppm.
 5. The process according to claim 1 wherein theperoxygen compound is selected from the group consisting of hydrogenperoxide, sodium peroxide, sodium perborate, potassium monopersulfate,sodium peroxydisulfate, potassium peroxide, potassium perborate, sodiummonopersulfate, potassium peroxydisulfate, ammonium peroxydisulfate andammonium monopersulfate.
 6. The process according to claim 1 furtherincluding the step of monitoring and controlling pH.
 7. A process forremoving dissolved halogenated compounds including chloramines and/orbromamines and preventing their accumulation in circulating watersystems comprising:disposing an oxidation-reduction potential (ORP)sensor in fluid communication with said circulating water system;continuously monitoring the ORP of said system; comparing the monitoredORP to a set-point value calculated to be within a range effective topermit oxidation of said halogenated compounds wherein the effectiverange of ORP is from 750 mv-850 mv; adding a halogen donor source in anamount and at a rate sufficient to realize an optimum free halogen levelsufficient to sanitize said body of water; adding a peroxygen compoundat a rate and in an amount sufficient to maintain the ORP within saideffective range; optimizing the ratio of halogen donor source toperoxygen compound to sustain the optimum free halogen level whilemaintaining the effective ORP value; and maintaining a sustained highrate of oxidation in said body of water sufficient to destroy anydissolved halogenated compounds within said body of water and preventfurther accumulation thereof.
 8. The process according to claim 7wherein said halogen donor source is selected from the group consistingof gaseous chlorine, calcium hypochlorite, sodium hypochlorite, lithiumhypochlorite and mixtures thereof.
 9. The process according to claim 7wherein the effective range of ORP is from 760 mv-800 mv.
 10. Theprocess according to claim 7 wherein the optimum free halogen level iswithin a range of 0.2 to 10.0 ppm.
 11. The process according to claim 7wherein the peroxygen compound is selected from the group consisting ofhydrogen peroxide, sodium peroxide, sodium perborate, potassiummonopersulfate, sodium peroxydisulfate, potassium peroxide, potassiumperborate, sodium monopersulfate, potassium peroxydisulfate, ammoniumperoxydisulfate and ammonium monopersulfate.
 12. The process accordingto claim 7 further including the step of monitoring and controlling pH.